2mm square push broach?

[Hauk]

Hi,
I need to clean up some square holes in rather small brass castings.

The holes are 2mm X 2mm and about 4mm deep. They go all the way through the casting, so clearing out chips is not an issue.

I have found several 2mm X 2mm rotating square broaches, but this concept is a bit too advanced for my use.

What I am looking for is a simple push-type broach. Tolerances are not too tight.

Is something like this available commercially? Or do I have to grind my own? If I need to grind my own I would love to see a drawing with the correct angles/rakes.

Best regards,
Haavard H.

 

[BaronJ]

Hi Hauk,

Have a look at this thread, post 92.

http://www.homemodelenginemachinist.com/showthread.php?t=22047&page=10

It describes my hand slotting tool. I needed to put a 4 mm slot into a bronze bush. So I purchased a piece of 4 mm square tool steel. To do what you want I would buy a piece of 2 mm square, or even better if it didn't interfere with anything, a 2 x 4 mm section and then I would have both 2 and 4 mm broaches.

As far as sharpening is concerned I just treated it as I would a lathe tool bit.

HTH.

 

[Hauk]

Hi Hauk,

Have a look at this thread, post 92.

http://www.homemodelenginemachinist.com/showthread.php?t=22047&page=10

It describes my hand slotting tool. I needed to put a 4 mm slot into a bronze bush. So I purchased a piece of 4 mm square tool steel. To do what you want I would buy a piece of 2 mm square, or even better if it didn't interfere with anything, a 2 x 4 mm section and then I would have both 2 and 4 mm broaches.

As far as sharpening is concerned I just treated it as I would a lathe tool bit.

HTH.

Anyone know of a source for 2mm square tool steel? I could also use som 1,5X1,5mm tool steel.

Maybe watchmakers use such tiny tools?

Best regards,
Haavard H

 

[BaronJ]

Depending upon the tool suppliers around you 2 mm square is a common size, often used for small lathe boring bar bits. I have some 5/64" square that I use in one of mine.

 

[Theclockworks]

Depending upon the tool suppliers around you 2 mm square is a common size, often used for small lathe boring bar bits. I have some 5/64" square that I use in one of mine.

Could you not use silver steel

 

[Hauk]

I could possible use silver steel, but I still need a source for it!

The tool suppliers in my area stock very little of stuff like this, so I am entirely dependent on finding what I need online.

 

[Wizard69]

You could try these guys to see if they would do custom grinds: http://www.arwarnerco.com

You could also try MSCDirect, Travers and other online sellers. MSC does have 1.5mm bits listed.

Spend some time on the net. Google is your friend.

 

[Hauk]

You could try these guys to see if they would do custom grinds: http://www.arwarnerco.com

You could also try MSCDirect, Travers and other online sellers. MSC does have 1.5mm bits listed.

Spend some time on the net. Google is your friend.

Belive me, I do spend some time on the net searching for all kinds of stuff. But I have failed to find tool blanks or silver steel in the required dimensins (1,5X1,5mm or 2X2mm)

MSCDirect has a lot of interesting stuff, but as far as I could see, no tool blanks in the above sizes.

 

[BaronJ]

Unless you have some means for machining to size and hardening it, silver steel / drill rod is no use to you. There are a number of suppliers, "Michel Fox, Cromwells, Buck & Hickman etc that stock "Dormer, Presto, etc" HSS tool bits in both metric and imperial sizes from 1mm round and square forms upwards. Some have carbide tool bits as well.

 

[Wizard69]

Belive me, I do spend some time on the net searching for all kinds of stuff. But I have failed to find tool blanks or silver steel in the required dimensins (1,5X1,5mm or 2X2mm)

MSCDirect has a lot of interesting stuff, but as far as I could see, no tool blanks in the above sizes.

Well I'm pretty sure it was MSCDirect that I was looking at. They had 1.5 & 3 mm square listed. It would be a total pain in the but to do free hand but you could always grind 3 mm down. It would be easy with a tool grinder but most of us don't have one!

I would be the first to suggest that MSC's online catalogs suck.